Puffing of tobacco and tobacco products



United States PatentO PUFFIN G OF TOBACCO AND TOBACCO; PRODUCTS John M. B'aer, Chicago,

No Drawing. Application September 9, 1953, Serial No. 379,308

9 Claims. (Cl. 131-1) This invention relates to the puffing of tobacco and tobacco products. It is a continuation-in-part of my copending application, Serial No. 361,415, filed June 12, 1953, now Patent No. 2,653,093. This application is also a continuation-in-part of my application Nos. 34,821, 34,822, and 34,823, all now abandoned and all filed June 23, 1948; also, Serial No. 23,869, filed April 28, 1948, now abandoned, and Serial No. 189,679, filed October 11, 1950. Serial No. 189,679 has now become abandoned and a continuation-in-part application No. 296,963, filed July 2, 1952, is likewise filed and is now abandoned, but after the filing of this case.

The puffing of tobacco resolves itself into two phases. The first is the pufiing of the leaf material, and the second is the pufiing of the stem material. The pulling of leaf material is of value primarily in providing an additional bulk for the tobacco, which is of benefit in providing a better control of smoking characteristics.

With respectto the stems, the problem is quite different. In connection with the stems, these have hitherto not been useful in smoking tobacco in any large quantities. Inasmuch as they amount to about 20% by Weight of the tobacco and are potentially smokable, this represents a large economic loss.

Heretofore the stems have not been useful because of two main factors. In the first place, they do not provide the proper taste to the smoke or to a chewing tobacco; and secondly in a smoking tobacco they explode. The explosion is not a detonation in the normal sense, but causes a puff or minor explosion which seriously interferes with smoking and is highly unpleasant and undesirable.

The puffing of tobacco by the present means makes it possible to utilize the stems in smoking, a thing which has heretofore been suggested, but never heretofore accomplished.

In treating the leaf tobacco, this may be done while the leaf is in leaf form with stems, after the stems have been stripped, or after the stripped leaf has been cut. The process is to remove the air from the product, as by the process of Merriam & Wiles, U. S. Patent No. 2,080,179, issued May 11, 1937, or by any other process, and replacing the air with an atmosphere of steam at a low absolute pressure, as for example, from .2 to 2 inches of mercury absolute. Steam is then introduced to the material while under the vacuum to increase the pressure, moisture content and temperature of the product. For most leaf tobacco, the ultimate pressure will not greatly exceed atmospheric, normally not going above 10 pounds gauge. The rate of introduction of the steam is such as to insure uniformity of temperature and pressure throughout the mass and to avoid condensation of water therein. After the desired puffing pressure has been reached, the pressure is instantaneously reduced to substantially zero absolute.

The pulling reaction may be carried out in a pufiing vessel such as that shown in Doyle Patent No. 2,627,221, issued February 3, 1953 or Bancroft application, Serial o. 1' .e 1 April- .0-. 5 no abandqne u an ppa us co p ises a pressure chambe in which,

he tobac o s fir t e acua ed and.v then. steamed to prouce t e p tt n pressure. and an a jacent: chamber, ve y a ge in volume; h two beingc nneete by r ge ed d qrhe pres re, hamb r. is. normally y m d ii a n hap and. th d or encloses an. entire. end of he cylinde T e. unifies ch mbe is maintained under a high vacuum, for example and preferably the, pressure is about 2. o an nch. absolu e in the puttin eham e When the triggered door is opened, the pressure is, instantaneously reduced and during the pulling operation the evacuation equipment is kept running so as to maintain a low pressure in the pulling chamber. Normally, the pressure is not allowed to increase to a point over 2 inches of mercury absolute.

The pulling chamber likewise comprises an atmosphere substantially entirely of steam.

The result is that the entire operation is carried out in a substantially air-free atmosphere so that the resulting temperature is determined by the boiling point of Water under the particular pressure.

This is of extreme importance since it means that the tobacco product is instantaneously reduced in temperature or cold set so that when atmospheric pressure is reimposed while the product is in cold set condition, the plasticity which is necessary for pulling will not result in a collapse of the cells which were puffed. It, likewise, for the first time in a pulling operation, insures that heat deterioration of the product will not continue and since the entire process from the beginning of the evacuation to the final pufiing can be completed in less than three minutes, the tobacco does not have any substantial time at an elevated temperature which might alter its smoking characteristics adversely.

The leaf product may be maintained in the pufiing chamber under continued evacuation if it is desired to accomplish additional drying.

The preferred pufiing pressure is from 20 to 30 inches of mercury absolute and the normal outside range is from 10 inches absolute to 10 pounds gauge.

When stem material is being treated, the limits are somewhat broader at the upper end, but even with such material, it is preferred to stay within the range of 25 inches absolute to around 10 pounds gauge. The maintained vacuum into which pulling occurs is of the same range as that for the leaf tobacco, although when higher pufiing pressures are used, it is possible to permit higher run-ups in the maintained vacuum; but in any event it is not preferred togo above 8 inches absolute.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

I claim:

1. In the puffing of tobacco, the steps of heating by steam the material in the absence of air to increase the moisture content, the temperature and the steam pressure thereon and then pulling the product into a maintained vacuum sufficiently low to cold set the product by evaporation of moisture from the consequent cooling of the product and reimposing atmospheric pressure upon the product While in cold set condition.

2. The method of claim 1 in which the maximum pressure does not exceed atmospheric.

3. The method of claim 1 in which the tobacco is leaf material.

4. The method of claim 1 in which the tobacco is stem material.

5. Pulfed tobacco produced by the process of claim 1.

6. Puffed leaf tobacco produced by the process of claim 1.

7. Puffed stern tobacco produced by the process of claim 1. V I

8l ln the' puffing of cellular material, the steps of heating the material in the absence of air by the addi-' tion of steam at a"pressure not greater than atmospheric toincrease the temperature and the steam pressure thereon and then pufling the product into a maintained vacuum sufiiciently low to cold set the product by evaporation of moisture from and consequent cooling of the product and reimposing atmospheric pressure upon the product while in cold set condition.

9. Puffed cellular material other than cereals produced by the process of claim 8.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN THE PUFFING OF TOBACCO, THE STEPS OF HEATING BY STEAM THE MATERIAL IN THE ABSENCE OF AIR TO INCREASE THE MOISTURE CONTENT, THE TEMPERATURE AND THE STEAM PRESSURE THEREON AND THEN PUFFING THE PRODUCT INTO A MAINTAINED VACCUM SUFFICIENTLY LOW TO COLD SET THE PRODUCT BY EVAPORATION OF MOISTURE FROM THE CONSEQUENT COOLING OF THE PRODUCT AND REIMPOSING ATMOSPHERIC PRESSURE UPON THE PRODUCT WHILE IN COLD SET CONDITION. 